Device consisting at least of two parts joined together

ABSTRACT

Two parts which form a device and are joined together according to the related art are joined in a complex manner and require additional elements to produce a tight joint. 
     A device ( 1 ) is described which has two parts ( 3, 6 ), has welding pockets ( 9 ) which are capable of receiving material during the welding operation for producing a joint.

BACKGROUND INFORMATION

The present invention is directed to a device according to the preambleof claim 1.

Joining two parts by a threaded joint is generally known. Thus, forexample, an insertion probe of a device for determining a parameter of amedium flowing in the duct is placed in a duct at least partially bybeing screwed onto a wall of the duct. In addition, further sealingelements such as rubber rings for example must be present on theinsertion probe to seal the duct outward. Screwing in is an additionalprocess step after the installation of the insertion probe in the duct.In addition, a further component, namely the sealing element, must beinstalled. Such a device is shown in U.S. Pat. No. 5,804,718, forexample.

ADVANTAGES OF THE INVENTION

The device according to the present invention having the characterizingfeatures of claim 1 has the advantage over the related art that a joint,which is moisture- and air-tight without additional means, is easilyestablished between two parts.

The presence of welding pockets when two parts are welded together isadvantageous, because material from at least one of the parts enters thewelding pocket and is thus unable to affect the joining process betweenthe two parts. In addition, the material which flows or is deformedduring the welding operation cannot reach the environment because it isheld in the welding pocket.

The at least one welding pocket may advantageously be present on one oron both parts. Furthermore, the interaction of the two parts may alsoresult in the formation of an advantageous welding pocket.

It is advantageous if a second part has a first projection, on which thefirst part rests during welding, because a defined welding pocket whichproduces a tight joint between the parts is thus produced.

It is advantageous if the parts are joined by orbital vibration welding,because this method subjects the parts and/or components situated on theparts to less thermal and mechanical stress compared to ultrasoundwelding. Thus, for example, a heat-sensitive and/or vibration-sensitiveelectronic component may be placed on at least one part before thewelding operation without being damaged by the welding operation.

DRAWING

Exemplary embodiments of the present invention are schematicallyrepresented in the drawing and explained in detail in the descriptionthat follows.

FIG. 1 shows a first exemplary embodiment of a device designed accordingto the present invention.

FIG. 2, show two additional exemplary embodiments of a device 2 a, 2 bdesigned according to the present invention;

FIG. 3 shows a device designed according to the present invention havinga first projection;

FIG. 4 a shows a device designed according to the present inventionhaving a second projection; and

FIG. 4 b shows a device shows in which the two parts are weldedtogether.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIG. 1 shows a first part 3 and a second part 6 of a device 1 designedaccording to the present invention.

The two parts 3, 6 are welded together.

Device 1 has, for example, a duct forming second part 6 and an insertionprobe 3 forming first part 3, which is inserted into the duct through aninsertion opening 7, at least one parameter of a medium flowing in theduct being determined using a sensor in insertion probe 3. Such a deviceis known, for example, from German Patent Application 198 27 375 A1 andshould be part of this disclosure.

Parts 3, 6 are made, for example, but not necessarily, of plastic andhave a central axis 21, for example. One axial end 4 of first part 3 isdesigned with a T-shaped cross section, for example. First part 3 issituated at least partially in second part 6, for example, and rests onsecond part 6, part 6 having a tubular design in the area of T-shapedend 4 of part 3.

In a radial direction 27 between first part 3 and second part 6, thereis a distance d different from zero, whereby a cavity acting as awelding pocket 9 is formed between first part 3 and second part 6.

During the welding operation, material may be eroded from or pressed offat a contact surface 33 between T-shaped end 4 of first part 3 andsecond part 6. This material enters the at least one welding pocket 9and no longer interferes with the welding operation between first part 3and second part 6.

Vibration welding, in particular orbital vibration welding, which isbased on friction heating and plasticizing of parts 3, 6 in the area ofcontact surface 33, by may be used as the welding process. It is carriedout via a unidimensional, oscillating or biaxial relative motion havingadjustable amplitudes of 0.25 to 2.5 mm and frequencies between 80 and300 Hz, for example, under a simultaneously acting pressure of P=0.5 to8.0 MPa exerted perpendicularly to contact surface 33.

FIG. 2 a shows an additional exemplary embodiment of a device 1 designedaccording to the present invention.

Welding pocket 9 is formed, for example, only on second part 6 byintroducing a depression in an inner wall 10 of second part 6 in theproximity of contact surface 33 to form welding pocket 9.

This depression to form welding pocket 9 may also be only on first part3 in an outer wall 11 in the proximity of contact surface 33 (FIG. 2 b).Distance d in the radial direction between first part 3 and second part6 may then be zero or very small.

FIG. 3 shows an additional exemplary embodiment of a device 1 designedaccording to the present invention.

Second part 6 has a first projection 12, which extends in the axialdirection, i.e., runs parallel to central axis 21 and has contactsurface 33 at an axial end. First projection 12 extends centrally, forexample, from a base surface 22 of part 6.

Welding pocket 9 is delimited in radial direction 27 by first projection12 and an outer wall 11 of first part 3, which is opposite firstprojection 12 in radial direction 27. In axial direction 21, weldingpocket 9 is delimited by base surface 22 of part 6 and the T head ofaxial end 4 of part 3.

The space facing outward in radial direction 27 of first projection 12also forms a welding pocket 9.

FIG. 4 a shows an additional exemplary embodiment of a device 1 designedaccording to the present invention.

Second part 6 has a second projection 15, which is situated on the outerradial edge of second part 6, i.e., on the outside opposite firstprojection 12 in radial direction 27 and extends in axial direction 21.Contact surface 33 of second part 6 with first part 3 is formed on firstprojection 12 and not on second projection 15. During the weldingoperation, the axial end of first projection 12 and first part 3 in thearea of contact surface 33 are heated and plasticized, so that material18 enters welding pockets 9 radially inward and outward.

Part 18 of first projection 12 which is deformed is identified bycross-hatching.

FIG. 4 b shows the two parts 3, 6 of a device 1 designed according tothe present invention when welded together.

Contact surface 33 forms a sealing surface 24 against air and moisture.

Second projection 15 of second part 6 may, but does not need to, rest onfirst part 3 and prevents material 18, which is present in outer weldingpocket 9, from escaping out of outer welding pocket 9 to the outside.

1. A device, comprising: at least two parts that are joined together,wherein: the at least two parts are welded together, at least onewelding pocket is present and is capable of receiving material of atleast one of the at least two parts that is displaced when the at leasttwo parts are welded together, one of the at least two parts includes afirst projection extending in an axial direction parallel to a centralaxis of the at least two parts and having a contact surface at an axialend, another one of the at least two parts rests on the contact surfaceof the first projection, the two parts welded together at a welding spotin an area of the contact surface, and one of the at least two parts issituated at least partially in another one of the at least two parts,the another one of the at least two parts in which the one of the atleast two parts is situated includes the first projection and a secondprojection that surrounds a welding spot at the first projection in aradial circumferential direction and that extends in the axialdirection.
 2. The device as recited in claim 1, wherein: the device isfor determining at least one parameter of a medium flowing in a duct. 3.The device as recited in claim 1, wherein: at least one of the at leasttwo parts includes the at least one welding pocket.
 4. The device asrecited in claim 1, wherein: the at least one welding pocket is formedby the at least two parts.
 5. The device as recited in claim 1, wherein:a tight joint exists between the at least two parts due to the welding.6. The device as recited in claim 1, wherein: the at least two parts arewelded together by vibration welding.
 7. The device as recited in claim6, wherein: the vibration welding includes orbital vibration welding. 8.The device as recited in claim 6, wherein: one of the at least two partsincludes at least one of a heat-sensitive electronic component and avibration-sensitive electronic component.